(a) Field of the Invention
The present invention relates to a writing instrument, more particularly to a writing instrument that permits smooth flow of ink when in use and ensures against dripping.
(b) Description of the Prior Art
Writing instruments are indispensable articles, and there are a great variety of writing instruments on the market. Some vary in terms of function, some in design.
Apart from the common pencils, ball point pens and fountain pens, there are a type of pen of a relatively large nib that is used for marking, drawings, such as markers, sign pens, felt pens, etc. One characteristic of such pens is that the barrel thereof contains an ink absorbing sponge that absorbs and holds the ink, and the nib is formed from a fiber capable of performing capillary action. The nib is communicated with the ink absorbing sponge to obtain an ink supply so that it can be used for writing purposes.
In the above-mentioned pens, for instance, markers and sign pens, since the nib is exposed on the outside, the ink in the nib may become dry after a period of time, and the ink has to be refilled, which is rather inconvenient. There is another type of pen in which the ink absorbing sponge is eliminated. The nib directly presses an internal valve to cause the ink to flow to the nib. A disadvantage with such a construction is that the nib may become split after a period of use due to frequent pressing. Moreover, each pressing can allow only a limited amount of ink to the nib and hence permit only a limited number of words. Besides, improper pressing may result in rise of pressure, which makes the nib over-saturated with ink and drip.